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Roman55 [17]
2 years ago
8

In September 2011, Gallup surveyed 1,004 American adults and asked them whether they blamed Barack Obama a great deal, a moderat

e amount, not much, or not at all for U.S. economic problems. The results showed that 53% of respondents blamed Barack Obama a great deal or a moderate amount. Calculate the 99% confidence interval for the proportion of all American adults who blame Barack Obama a great deal or a moderate amount for U.S. economic problems.
Mathematics
1 answer:
Alexus [3.1K]2 years ago
3 0

Answer:

The 99% confidence interval for the proportion of all American adults who blame Barack Obama a great deal or a moderate amount for U.S. economic problems is (0.4894, 0.5706)..

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of \pi, and a confidence level of 1-\alpha, we have the following confidence interval of proportions.

\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}

In which

z is the zscore that has a pvalue of 1 - \frac{\alpha}{2}.

For this problem, we have that:

n = 1004, \pi = 0.53

99% confidence level

So \alpha = 0.01, z is the value of Z that has a pvalue of 1 - \frac{0.01}{2} = 0.995, so Z = 2.575.

The lower limit of this interval is:

\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.53 - 2.575\sqrt{\frac{0.53*0.47}{1004}} = 0.4894

The upper limit of this interval is:

\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.53 - 2.575\sqrt{\frac{0.53*0.47}{1004}} = 0.5706

The 99% confidence interval for the proportion of all American adults who blame Barack Obama a great deal or a moderate amount for U.S. economic problems is (0.4894, 0.5706)..

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AnnZ [28]

Answer:

See solution below

Step-by-step explanation:

According to pythagoras theorem

hyp^2 = opp^2 + adj^2

10^2 = 4^2 + b^2

100 = 16 + b^2

b^2 = 100-16

b^2 = 84

b = √84

b ≈ 9

Using SOH CHA TOA identity

sin B = AC/AB

Sin B = 9/10

B = arcsin0.9

B ≈ 64degrees

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5 0
2 years ago
(1) a) 5270 cl= ? dal
Ivanshal [37]

Answer:

Check below

Step-by-step explanation:

1) These metric volume units can be easily converted by dividing or multiplying by 10 and its multiple. Like this: each step up on the ladder multiply by 10. Each step down divide by 10

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2) When it comes to area, the "ladder scheme" remains valid but now we'll multiply or divide by

10^3

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6 0
3 years ago
A stack of logs has 32 logs on the bottom layer. Each subsequent layer has 6 fewer logs than the previous layer. If the top laye
Svetlanka [38]

Answer:  The total number of logs in the pile is 6.

Step-by-step explanation:  Given that a stack of logs has 32 logs on the bottom layer. Each subsequent layer has 6 fewer logs than the previous layer and the top layer has two​ logs.

We are to find the total number of logs in the pile.

Let n represents the total number of logs in the pile.

Since each subsequent layer has 6 fewer logs then the previous layer, so the number of logs in each layer will become an ARITHMETIC sequence with

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We know that

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a+(n-1)d=2\\\\\Rightarrow 32+(n-1)(-6)=2\\\\\Rightarrow 32-6n+6=2\\\\\Rightarrow 6n=36\\\\\Rightarrow n=6.

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3 years ago
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